Formula.Firewall and Refresh problems

Hi all,
I'm fairly new to Power Query -Ive created a file which combines 4 excel documents which are saved in a sharepoint folder into 1 data table, to do this I used the get data from Web option

Then I created a query from a sharepoint excel file into a pivot chart

It was originally working, i tested it and dropped new excel files into the folder and refreshed excel, it worked fine.

I then added some custom columns and filtered columns.

after a few days the refresh all stopped working, when I click on data refresh all the file freezes and excel is 'not responding'

If I refresh only the pivot chart it seems to reflect the correct information taken from the single excel file

After a couple of more days I noticed a message 'formula.firewall information about a data source is required' I amended to organizational.

Then Ive also amended all files to reflect organizational, in my workbook and global

I've also noticed in the query the source data doesn't show the updated new files, is this right?

I'm not combining the two data sets, but I would like to work from both in one workbook

Can anyone help me fix issues:
1. Fix the formula.firewall error
2. Fix the refresh all option

3. Any other issues you may think I have